In the existing technology, an IT system generally uses various standard pictures to facilitate identification by a machine during service transactions. For example, passport photo pictures, identity card pictures, social security card pictures, and driver's license pictures are often used for facilitating online transactions of a bank service, a financial service, and a social serving service. Frequently, digital documents that capture pages or photographs of paper identification documents via scanning or photographing means are also used to facilitate identification by machines during the service transactions. A relatively high resolution and non-shielding of key information of a standard picture usually need to be guaranteed since the standard picture is usually saved as a supporting document or used for machine identification, so that no ambiguity or false judgment of machine identification is generated. Therefore, generally there should not be interference information such as a watermark in a standard picture. The watermarks typically included on standard ID pictures often includes a pattern that spans the entire picture, but the features in the watermark is usually very fine and widely spaced, such that their presence do not prohibit general visual inspection of the standard ID pictures.
In the conventional technology, to identify a watermark contained in a standard picture document, generally an edge detection method is used for obtaining profile information of the standard picture, and then whether a profile satisfying watermark features (for example, diagonal texts, meshes, and super-large texts, referring to FIG. 1; Note: a mosaic is applied to the facial area in the image of the standard picture to protect personal privacy of the person in the standard picture, the mosaic pattern is not part of the actual standard picture or watermark), thereby identifying a watermark in the standard picture.
The method for identifying whether a standard picture contains watermark information in the conventional technology at least has the following problem: a portrait area in a standard picture, for example, in an identity card picture, usually further includes backgrounds such as clothes, and profile information that may cause interference with the identification of the watermarks is easily introduced by the presence of clothing in the standard picture, thereby resulting in false determination, and causing program failure or transaction failure, and wasted time and computing resources. In addition, the image processing involved in edge detection is processor and memory intensive, and require a powerful computer to perform, which prevents it from being used in terminal devices that have limited processing power and memory. Furthermore, the results produced by edge detection techniques are inconsistent, and a systematic error reduction technique cannot be applied to remedy the false detection results. Therefore, the accuracy of the method for identifying whether a standard picture contains watermark information in the conventional technology is not sufficient.